I’ve been interested in timekeeping devices for many years, and have generally been facinated with watches, and in the last year or so, I’ve become I big fan of mechanical ones.

I’ve been particularly interested in the Seiko automatics. I’ve not seen a better quality automatic watch anywhere in the price range, both in terms of the movement, and the case. The Seiko movements have proven, for the two of them that I’ve owned, to be very reliable and satisfyingly accurate.

The accuracy of a mechanical watch is really a marvel unto itself. With something like a grandfather clock, it has a large case, a long pendulum, ample space for the movement, plenty of space for the weights which provide for the power of the clock, and generally, a fairly stable operating temperature. If a grandfather clock were not extremely accurate, you’d be right to be very dissapointed.

In a wristwatch, you have basically none of those things. In a wristwatch, you have a comparatively miniscule case. This case must still house a movement, which often does even more than your grandfather clock, such as day/date functions or even a chronograph, or more. It will be run face-up, face-down, on it’s side, and so on. It still must provide for at least a day and a half of runtime before having to be wound from a spring whose force output changes as it unwinds. It must be able to take substantial impacts, and in the case of a certified diver’s watch the impact of a 3 kg hammer with an impact velocity of 4.43 m/s. Many cases must be water resistant to 20 atmospheres or more. Some must be relatively immune to magnetism. Some manage to even wind themselves off the motions of being worn. It will be running at much more variable temperatures, only mitigated somewhat from the body heat of the wearer. It should probably look nice too.

Oh yeah, and they should be accurate.

When you think that it’s not to hard to find a mechanical watch whose accuracy rating is +/- 15 seconds per day, that’s an error of only 0.017% per day, that’s pretty amazing. In my experience with my Seikos, I’ve had one that was +2/-4 seconds per day, and my current one is -5/-6 per day, which is about .007% per day.

Factor all that in and that you can buy a simple automatic watch for US$60 or less, or a divers watch for around US$150.

It’s quite remarkable to see the end products of the battle of the constraints of physics, fashion, finance, and features to produce a well regulated wristwatch.